19-1411; Rev 0; 12/98 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits The MAX6332/MAX6333/MAX6334 microprocessor (µP) supervisory circuits monitor the power supplies in 1.8V to 3.3V µP and digital systems. They increase circuit reliability and reduce cost by eliminating external components and adjustments. These devices perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for a preset timeout period after VCC has risen above the reset threshold. The only difference among the three devices is their output. The MAX6333 (push/pull) and MAX6334 (open-drain) have an active-low RESET output, while the MAX6332 (push/pull) has an active-high RESET output. The MAX6332/MAX6333 are guaranteed to be in the correct state for VCC down to 0.7V. The MAX6334 is guaranteed to be in the correct state for VCC down to 1.0V. The reset comparator in these ICs is designed to ignore fast transients on VCC. Reset thresholds are factorytrimmable between 1.6V and 2.5V, in approximately 100mV increments. There are 15 standard versions available (2,500 piece minimum-order quantity); contact the factory for availability of nonstandard versions (10,000 piece minimum-order quantity). For space-critical applications, the MAX6332/MAX6333/MAX6334 come packaged in a 3-pin SOT23. Features ♦ Ultra-Low 0.7V Operating Supply Voltage ♦ Low 3.3µA Supply Current ♦ Precision Monitoring of 1.8V and 2.5V PowerSupply Voltages ♦ Reset Thresholds Available from 1.6V to 2.5V, in Approximately 100mV Increments ♦ Fully Specified over Temperature ♦ Three Power-On Reset Pulse Widths Available (1ms min, 20ms min, 100ms min) ♦ Low Cost ♦ Three Available Output Structures: Push/Pull RESET, Push/Pull RESET, Open-Drain RESET ♦ Guaranteed RESET/RESET Valid to VCC = 0.7V (MAX6332/MAX6333) ♦ Power-Supply Transient Immunity ♦ No External Components ♦ 3-Pin SOT23 Package ♦ Pin-Compatible with MAX809/MAX810 and MAX6326/MAX6327/MAX6328 Applications Pentium II™ Computers Ordering Information Computers Controllers Intelligent Instruments Critical µP/µC Power Monitoring Portable/Battery-Powered Equipment Automotive Typical Operating Circuit and Pin Configuration appear at end of data sheet. Selector Guide appears at end of data sheet. PART* TEMP. RANGE PIN-PACKAGE MAX6332UR__D_-T -40°C to +85°C 3 SOT23-3 MAX6333UR__D_-T -40°C to +85°C -40°C to +85°C 3 SOT23-3 3 SOT23-3 MAX6334UR__D_-T * These devices are available in factory-set VCC reset thresholds from 1.6V to 2.5V, in approximately 0.1V increments. Choose the desired reset threshold suffix from Table 1 and insert it in the blanks following “UR” in the part number. Factory-programmed reset timeout periods are also available. Insert the number corresponding to the desired nominal reset timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in the blank following “D” in the part number. There are 15 standard versions with a required order increment of 2500 pieces. Sample stock is generally held on the standard versions only (see Selector Guide). Contact the factory for availability of nonstandard versions (required order increment is 10,000 pieces). All devices available in tape-and-reel only. Pentium II is a trademark of Intel Corp. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX6332/MAX6333/MAX6334 General Description MAX6332/MAX6333/MAX6334 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) VCC ......................................................................-0.3V to +6V Push/Pull RESET, RESET .......................-0.3V to (VCC + 0.3V) Open-Drain RESET ..............................................-0.3V to +6V Input Current (VCC) .............................................................20mA Output Current (RESET, RESET).........................................20mA Rate of Rise, VCC ............................................................100V/µs Continuous Power Dissipation (TA = +70°C) SOT23-3 (derate 4mW/°C above +70°C) ....................320mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = full range, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C and VCC = 3V, reset not asserted.) PARAMETER SYMBOL Supply Voltage Range VCC Supply Current ICC Reset Threshold VTH VCC Falling Reset Delay MAX633_UR__D_-T, Table 1 tRP RESET Output Low Voltage (MAX6333/MAX6334) VOL Reset asserted RESET Output High Voltage (MAX6333) VOH Reset not asserted VOH Reset asserted VOL Reset not asserted RESET Output Leakage Current (MAX6334) MIN 0.7 1.0 0.78 1.2 TYP 3.0 3.3 TA = +25°C VTH 1.8% VTH TA = -40°C to +85°C VTH 3% VTH VCC falling at 10V/ms MAX633_UR__D1-T MAX633_UR__D2-T MAX633_UR__D3-T Reset Active Timeout Period RESET Output Voltage (MAX6332) 2 CONDITIONS MAX6332/MAX6333 TA = 0°C to +85°C MAX6334 MAX6332/MAX6333 TA = -40°C to +85°C MAX6334 VCC = 1.8V No load VCC = 2.5V 1 20 100 24 1.5 30 150 MAX 5.5 5.5 5.5 5.5 6.0 7.0 VTH + 1.8% VTH + 3% 0.4 ISINK = 500µA, VCC ≥ 1.8V 0.3 0.8VCC ISOURCE = 500µA, VCC ≥ 2.7V 0.8VCC ISOURCE = 1µA, VCC ≥ 1.0V 0.8VCC ISOURCE = 200µA, VCC ≥ 1.8V 0.8VCC V ms V V 0.3 ISINK = 1.2mA, VCC ≥ 2.7V 0.3 _______________________________________________________________________________________ µA V ISINK = 500µA, VCC ≥ 1.8V Reset VCC > VTH, RESET deasserted asserted V µs 2 40 200 ISINK = 50µA, VCC ≥ 1.0V ISOURCE = 200µA, VCC ≥ 1.8V UNITS 0.5 V µA 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits VCC = 2.5V 3.0 VCC = 1.8V 2.8 2.6 2.4 2.2 1.010 1.000 0.990 0.980 -20 0 20 40 60 80 100 40 MAX6332/33/34 toc-6 TA = +25°C TA = +85°C 30 20 TA = -40°C 0 -40 -20 0 20 40 60 80 0.5 100 1.00 1.50 2.00 2.50 3.00 TEMPERATURE (°C) TEMPERATURE (°C) VCC (V) OUTPUT VOLTAGE HIGH vs. SUPPLY VOLTAGE MAXIMUM TRANSIENT DURATION vs. RESET COMPARATOR OVERDRIVE VCC FALLING PROPAGATION DELAY vs. TEMPERATURE 140 120 600 100 80 60 TA = +25°C 40 TA = -40°C 500 400 RESET OCCURS 300 200 RESET DOES NOT OCCUR 100 80 70 PROPAGATION DELAY (µs) VTH = 2.2V ISOURCE = 100µA RESET ASSERTED MAXIMUM TRANSIENT DURATION (µs) 160 20 50 10 -60 MAX6332/33/34 toc-5 -40 60 0.970 0.950 -60 VTH = 2.5V ISINK = 500µA RESET ASSERTED 70 0.960 RESET NOT ASSERTED 2.0 OUTPUT VOLTAGE HIGH (VCC - VOH) (mV) 1.020 80 MAX6332/33/34 toc-3 3.2 1.030 MAX6332/33/34 toc-4 ICC (µA) 3.4 VTH = 2.2V 1.040 OUTPUT VOLTAGE LOW (mV) 3.6 1.050 MAX6332/33/34-2 3.8 NORMALIZED RESET TIMEOUT PERIOD MAX6332/33/34 toc-1 4.0 OUTPUT VOLTAGE LOW vs. SUPPLY VOLTAGE NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 60 VCC FALLING AT 1V/ms 50 40 30 VCC FALLING AT 10V/ms 20 TA = +85°C 10 0 0 0.1 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 VCC (V) 1 10 100 1000 RESET COMPARATOR OVERDRIVE (mV) -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Pin Description PIN NAME FUNCTION 1 MAX6333 MAX6334 1 — 2 RESET Active-Low Reset Output. RESET remains low while VCC is below the reset threshold and for a reset timeout period (tRP) after VCC rises above the reset threshold. RESET on the MAX6334 is open-drain. 2 — RESET Active-High Reset Output. RESET remains high while VCC is below the reset threshold and for a reset timeout period (tRP) after VCC rises above the reset threshold. 3 3 VCC MAX6332 GND Ground Supply Voltage (0.7V to 5.5V) _______________________________________________________________________________________ 3 MAX6332/MAX6333/MAX6334 Typical Operating Characteristics (Reset not asserted, TA = +25°C, unless otherwise noted.) MAX6332/MAX6333/MAX6334 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits ______________Applications Information VCC Interfacing to µPs with Bidirectional Reset Pins VCC Since the RESET output on the MAX6334 is open-drain, this device interfaces easily with µPs that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the µP supervisor’s RESET output directly to the microcontroller’s (µC’s) RESET pin with a single pull-up resistor allows either device to assert reset (Figure 1). Negative-Going VCC Transients In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, these devices are relatively immune to short-duration, negative-going VCC transients (glitches). The Typical Operating Characteristics show the Maximum Transient Duration vs. Reset Comparator Overdrive graph. The graph shows the maximum pulse width that a negative-going VCC transient may typically have without issuing a reset signal. As the amplitude of the transient increases, the maximum allowable pulse width decreases. Ensuring a Valid Reset Output Down to VCC = 0 When VCC falls below 1V and approaches the minimum operating voltage of 0.7V, push/pull-structured reset sinking (or sourcing) capabilities decrease drastically. High-impedance CMOS-logic inputs connected to the RESET pin can drift to indeterminate voltages. This does not present a problem in most cases, since most µPs and circuitry do not operate at VCC below 1V. For the MAX6333, where RESET must be valid down to 0, adding a pull-down resistor between RESET and GND removes stray leakage currents, holding RESET low (Figure 2a). The pull-down resistor value is not critical; 100kΩ is large enough not to load RESET and small enough to pull it low. For the MAX6332, where RESET must be valid to VCC = 0, a 100kΩ pull-up resistor between RESET and VCC will hold RESET high when VCC falls below 0.7V (Figure 2b). Since the MAX6334 has an open-drain, active-low output, it typically uses a pull-up resistor. With this device, RESET will most likely not maintain an active condition, but will drift to a non-active level due to the pull-up resistor and the reduced sinking capability of the opendrain device. Therefore, this device is not recommended for applications where the RESET pin is required to be valid down to VCC = 0. VCC µP MOTOROLA 68HCXX RESET INPUT MAX6334 RESET GND GND Figure 1. Interfacing to µPs with Bidirectional Reset Pins VCC VCC 100k* MAX6333 MAX6332 RESET RESET 100k GND (a) GND (b) *ASSUMES HIGH-Z RESET INPUT TO THE µP Figure 2. Ensuring Reset Valid Down to VCC = 0 Table 1. Factory-Trimmed Reset Thresholds* RESETTHRESHOLD SUFFIX MAX633_UR25D_ MIN TYP MAX MIN MAX 2.46 2.50 2.55 2.43 2.58 MAX633_UR24D_ 2.36 2.40 2.44 2.33 2.47 MAX633_UR23D_ 2.26 2.30 2.34 2.23 2.37 MAX633_UR22D_ 2.16 2.20 2.24 2.13 2.27 MAX633_UR21D_ 2.06 2.10 2.14 2.04 2.16 MAX633_UR20D_ 1.96 2.00 2.04 1.94 2.06 MAX633_UR19D_ 1.87 1.90 1.93 1.84 1.96 MAX633_UR18D_ 1.77 1.80 1.83 1.75 1.85 MAX633_UR17D_ 1.67 1.70 1.73 1.65 1.75 MAX633_UR16D_ 1.57 1.60 1.63 1.55 1.65 TA = +25°C TA = -40°C to +85°C * Factory-trimmed reset thresholds are available in approximately 100mV increments, with a ±1.8% room-temperature variance. 4 _______________________________________________________________________________________ 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits Typical Operating Circuit TOP VIEW VCC GND 1 MAX6332 MAX6333 MAX6334 VCC VCC MAX6332 MAX6333 µP 3 VCC RESET (RESET) RESET INPUT GND GND RESET (RESET) 2 SOT23-3 ( ) ARE FOR MAX6332 ( ) ARE FOR MAX6332 Selector Guide (standard versions*) PART OUTPUT STAGE NOMINAL VTH (V) MINIMUM RESET TIMEOUT (ms) SOT TOP MARK MAX6332UR23D3-T Push/Pull RESET 2.30 100 FZDM MAX6332UR22D3-T Push/Pull RESET 2.20 100 FZCN MAX6332UR20D3-T Push/Pull RESET 2.00 100 FZDL MAX6332UR18D3-T Push/Pull RESET 1.80 100 FZCM MAX6332UR16D3-T Push/Pull RESET 1.60 100 FZCL MAX6333UR23D3-T Push/Pull RESET 2.30 100 FZCS MAX6333UR22D3-T Push/Pull RESET 2.20 100 FZCR MAX6333UR20D3-T Push/Pull RESET 2.00 100 FZCQ MAX6333UR18D3-T Push/Pull RESET 1.80 100 FZCP MAX6333UR16D3-T Push/Pull RESET 1.60 100 FZCO MAX6334UR23D3-T Open-Drain RESET 2.30 100 FZDO MAX6334UR22D3-T Open-Drain RESET 2.20 100 FZCV MAX6334UR20D3-T Open-Drain RESET 2.00 100 FZDN MAX6334UR18D3-T Open-Drain RESET 1.80 100 FZCU MAX6334UR16D3-T Open-Drain RESET 1.60 100 FZCT * Sample stock is generally held on all standard versions. _______________________________________________________________________________________ 5 MAX6332/MAX6333/MAX6334 Pin Configuration Chip Information TRANSISTOR COUNT: 505 Package Information SOTPO3L.EPS MAX6332/MAX6333/MAX6334 3-Pin, Ultra-Low-Voltage, Low-Power µP Reset Circuits Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.